DC Sputtered ZnO ozone sensors for ultra-low limits detection operating at room
temperature
D. Katerinopoulou
1,2
, K. Moschovis
1,2
, E. Gagaoudakis
1,2
, E. Aperathitis
2
, V. Binas
2
,
and G. Kiriakidis
1,2
1
Physics Department, University of Crete, P.O. Box 2208, 71003 Heraklion, Crete, Greece
2
Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology
(FORTH) Hellas, P.O. Box 1385, Heraklion 70013, Crete, Greece
E-mail:
Sensing of hazardous gases is of great importance during the last decades. For this
purpose many materials, mainly metal oxides, have been studied and tested in as far as their
sensing characteristics are concerned. Zn oxide is well-known wide band gap semiconductors
that are used in many applications due to its excellent optical, structural and electrical
properties. Among its surface chemical sensitivity along with the variation of conductivity
when reacting with oxidizing gases, such as ozone, makes it appropriate candidate as gas
sensing material [1].
In the present work, ZnO films were produced by dc magnetron sputtering method
using a metallic targets, at room temperature. The material was deposited on both glass
substrates with NiCr contacts and Surface Acoustic Waves (SAW) filters [2] and was tested
towards ozone via two different means; by recording conductivity changes and by monitoring
the central frequency shift of the SAW filter, respectively.
It was found that conductivity was decreased of several orders by magnitude in the
presence of 5-2000 ppb ozone concentrations at room temperature. Corresponding results
regarding high frequency SAW filters (930MHz central frequency) revealed a frequency shift
of a few MHz towards 1 ppm ozone pulses at 150°C. Elaboration of additional results and
sensing performance on lower filter frequency SAWs will be presented.
[1]
M. Bender, E. Fortunato, P. Nunes, A. Marques, R. Martins,
N. Katsarakis, V. Cimalla and
G. Kiriakidis, “Highly Sensitive ZnO Ozone Detectors at Room Temperature”, Jap. J. Appl. Phys. 42
(2003).
[2] G. Kiriakidis, K. Moschovis, I. Kortidis, V. Binas
“Ultra-Low Gas Sensing utilizing Metal Oxide Thin
Films” Vacuum 86 (2012) 495-506
PS2 11
-205-
